They say two possible sites where Fiona's remains may be buried have been identified and they are waiting the go-ahead from Operation Trace to search them.

The most recent dig was a couple of months ago which resulted in a sample of what was believed to be human hair was sent for DNA analysis.

Subsequently, the sample was tested by the gardai and ruled out of the investigation.

The site where the sample was recovered from was highlighted by Joe Blake of Trace Missing Persons Ireland, who had travelled to Wexford with specially trained dogs, prompting members of the family to dig the area.

Fiona has been missing from the home in Bridgetown since February 1998 and despite extensive investigations by the gardai no trace of her has been found.

'We're still looking for Fiona and would appreciate any information,' said her sister Diane.

One of Fiona's cousins, Marie, said two potential sites had been identified in May, one more significant than the other.

'We're just waiting for permission from Operation Trace for the two sites to be searched,'she said, adding that information about them 'came from very reliable sources'.

'We're gathering all the intelligence, putting it together and working with the gardai,' said Marie, 'this could be sometime in September.'